


Costume Contest

by PitchBlackWings



Series: FluffMare [2]
Category: Undertale (Video Game)
Genre: Contests and Games, Costumes, Fluff, Fun, Halloween, M/M, Spoopy Cross, Spoopy Horror, Spoopy everyone really, halloween party
Language: English
Status: Completed
Published: 2019-10-31
Updated: 2019-10-31
Packaged: 2021-01-05 21:24:07
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,115
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21215300
Author URL: https://archiveofourown.org/users/PitchBlackWings/pseuds/PitchBlackWings
Summary: A Halloween special.The Dark Sanses decide to have a little Halloween party at the hideout.  Shenanigans ensue when the gang decides on a game to play.





	Costume Contest

**Author's Note:**

> Let the Halloween fun begin! :3
> 
> And yes i just had to add Errormare. ;3

Fresh walked into the hideout AU through the portal he had made. What was all this about?  
He had gotten an invitation to come to some sort of costume party...

He knocked on the door, adjusting his hat. He had come as a pirate, down to a small stuffed parrot clipped to his shoulder. The colors were vibrant, and he liked how they looked at the store.

Footsteps sounded, someone walking towards the door. "Hold on a second!"

Someone opened the door.

Fresh jumped back in surprise as he was met with a furry skeleton with a hole in its skull.

Upon closer inspection, it was Horror in a werewolf costume. The Dark Sans had furry facepaint all over his skull, tattered clothing with furry sleeves, clawed wolf paws, and a tail as part of his costume.  
He smiled, showing that he had even put removeable fangs on his sharp teeth.

"Hey, Fresh," he said cheerfully. "glad you could make it! Is that a parrot?"

Fresh smiled and pressed the stomach of his parrot, clicking a button hidden in its fluff and feathers.  
"AWKK! Polly want a Furby! AWKK!"

Horror laughed. "Leave it to you to get a 'fresh' parrot, buddy. Come on in!"

Fresh walked into the living room, staring at the decorations. Fake cobwebs were draped along the walls, along with plastic spiders. Jack-O-lantern streamers were everywhere, draped from the ceiling.  
There was a stuffed black cat on the sofa, and the refreshment table was stuffed with spooky-themed foods.

Nightmare was in the living room with the others, evidently waiting for Fresh and Horror to show up. The inky skeleton was wearing none other than an octopus costume, a few tentacles waving from sleeves at the back.

Error was sitting next to him on the couch, dressed as... Fresh had no idea. Some sort of red and blue one piece with a spider on the chest?

Dust was dressed as a Mad Scientist, wig and all, vials with colored water hanging at a belt on his vest.  
At least, Fresh hoped that it was just colored water.

Cross was dressed as a vampire, cape at his back, tips of fake 'bloodstained' fangs showing. His Victorian-like outfit seemed just as complicated as his normal everyday outfit, if not moreso.

And Killer was dressed as a zombie, his bones stained green and his clothes torn. He had even added fake scars and bags under his eyes, making it look super realistic.

Horror let out a long howl to go with his costume's character, announcing their enterance.  
"Freshy's here!"

-  
\--  
\---  
\----  
\---  
\--  
-

Fresh was sitting on the couch a few minutes later after getting caught up on news. It was time for party games- whatever the others had planned. Probably nothing deadly.  
Probably.

"Alright, what about acting for the first game? Whoever can stay most in their costume's character wins the prize. Everyone else can vote," Nightmare suggested.

"Sounds good," Dust said, echoing the popular verdict around the room. "Who wants to go first?"  
Error raised a few fingers, indicating that he wished to be the first to act.

Fresh frowned.  
"Who are you supposed to be again?"

Error rolled his eyes as Cross giggled.  
"I'm sPiDeR-mAn," he explained. "He'S a SuPeRhErO wItH tHe pRoPoRtiOnAl sTrEnGtH aNd pOwErS oF a sPiDeR, aNd hE cAn sHoOt wEbS."

Fresh nodded. That sort of made sense. There was a spider on the costume, after all. That did sound pretty cool, though. He could walk on walls and shoot webs?

Error got up, turning to face the others. "WhAt sHoUlD I dO?" he asked.  
"Swing around like Spider-Man!" Dust suggested, excitement on his skull.

Error nodded, making a strange pose with his fingers, folding down the middle and ring finger. Blue shring shot out from his sleeve, seeming to come from his hands.  
The string wrapped around a (very sturdy) chandelier across the room, then retracted and tightened, letting Error shoot across the room towards it.

At the last possible second, Error let go of the string, doing a somersault and landing on the floor in a dramatic pose, one hand and one knee steadying himself on the floor.  
He stood up and walked to the couch after taking a bow.

Fresh held up a scorecard (Nightmare had somehow passed them out with his tentacles beforehand.), showing a large black 7.  
Horror held up an 8.  
Dust an 8 as well.  
Killer a 7.  
And Nightmare held up a golden 10.

"Are you sure you aren't biased, Dad?" Dust asked jokingly.  
"No," Nightmare said, straight-faced. "But biased or not, it's my opinion."

Fresh snorted.

Horror was next.

"Just... do something werewolves do," Killer said, shrugging. "I have no idea."

Stepping forwards, the skeleton turned both of his eyelights large and dark red, hunching over to look more animalistic. He tilted his head back and let out a deep, throaty howl, showing off realistic fangs.  
He then fake-lunged at Nightmare, snarling with malice.

Nightmare didn't flinch whatsoever, leaving Horror toppled on the goopy skeleton's lap.

Nightmare stared at him, fighting an amused smile. He held up a 7.  
Cross placed an 8, Killer an 8, Dust a 6, Error an 8, and Fresh a 9. He had been sort of shaken by the howl...

The next was Killer.

"Do a zombie walk," Cross suggested, staring expectantly at his fellow gang member.

Killer leaned over, screwing his legs and arms to look unnatural, letting a low moan slowly emanate from his skull, letting his eyelights go out. He slowly shuffled forwards, reaching out a clawed hand for his audience.  
With a sudden clatter, the arm fell off, rolling to the floor. Killer paid it no mind as he continued to advance.

In the blink of an eye, Killer stopped shuffling, rushing forwards with blurring speed to the couch his family was sitting on, leaning forwards and exposing sharp teeth with a low growl.

Cross jolted back along with Dust. Geez, that had scared them...

They both held up a 9. Fresh showed an 8, Nightmare a 7, Error a 9 as well, and Horror an 8.  
Everyone had flinched at the end except Nightmare.

"Gosh darn it, dad, do you ever get scared??" Killer asked exasperatedly, picking up his arm and reattatching it to his elbow.

"Sometimes," Nightmare said, a smug smile on his face. "But not often."

Dust was next.

"What do I even do??" He asked, holding up his phalanges confusedly. "What under Earth would a mad scientist even do, create Frankenstein??"  
Nightmare shrugged. "Make a cool chemical reaction or something."

Dust took two vials from his belt, changing his eyelight colors sporadically to exaggerate the idea of a "mad" doctor.  
He threw the vials on the ground, breaking them and mixing the liquid. He took another vial from his chest sash, showing off the pure black liquid inside.

"Experiment 093346," Dust rasped out in a wheezing voice that rose and undulated unpredictably. "The chemicals have reacted perfectly. Now to add the essential essence..."

He ripped off the cork, pouring the liquid into the pre-existing puddle.  
A huge cloud of black smoke erupted, purple wisps seeming to form eyes and a huge, gaping mouth on a mass of swirling smoke.  
Above the hissing of the reaction, Dust's voice could be heard-  
"IT'S ALIVE!!!!!!!"

Nightmare raised an eyebrow, holding up a 5.  
"Aww, come on!"  
The goopy skeleton rolled his eyes. "It was okay until you used that terrible cliche. Then it just kinda got ruined for me."

Fresh, Dust and Cross all showed 7 on their cards. Error showed an 8, and Horror displayed a 6.

"Fresh, do you want a turn?" Nightmare looked at the pirate-clad skeleton questioningly.

Fresh thought for a moment before shaking his head. He had no idea what pirates really did, and he didn't like preforming. It was super fun just to watch all the others play.  
"I'm good," he replied.

Nightmare shrugged. "It's your turn then, Cross."

Cross blinked, standing up. "What should I do?"

"Do a dissapearing and reappearing thing that vampires do in the shadows in horror movies," Dust suggested.  
"Terrible B-rated abominations of movies," Killer snorted. "Don't even get me started on Vampyre Kingdom II-"

Nightmare whacked him on the back of the head playfully. "Shut up. It was a classic."

Cross adjusted his standing position, almost unnaturally stiff with a tinge of aggression. His eyelights swept the 'audience', inspecting them.  
Sweeping his cloak around him, he strode slowly and purposely to the hallway, where the lights were off. It was pretty dark in there...

With a last _swish_ of his cloak, he vanished into the shadows, smoke swirling from where he once was. Eyes roamed the nearby area, searching for him.

A low laugh seemed to echo throughout the room, unnerving the Monsters watching.

Suddenly, a whisper came from behind everyone's heads.

"_Boo._"

Almost everyone jolted to see Cross, his eyelights glowing and his fangs bared in a malicious smile.

Everyone except Killer.

And Nightmare. Predictably.

Fresh held up a 10. From the movies he had seen and the books he had read, that was a really accurate portrayal...  
Horror showed an 8, Killer a 7, Dust a 9, Error and Nightmare both 8 as well.

"It's your turn, Nightmare," Fresh pointed out.  
If he was honest, he was kind of confused. How was Nightmare supposed to act like an octopus?

"Uhh... just act like an octopus, i guess," Killer said, his tone confused as well.

Nightmare got up, standing a considerable distance away, a look of concentration in his eyelight.

The corruption flowing down his form ran faster, seeming to change shape. The ooze began to...  
...Shrink?

Once the change was finally done, there was a tiny, oozing, black Octopus on the floor, waving eight tentacles.

Fresh stared.  
"How in the world is he doing that?"

Horror was trying to stop laughing. "Nightmare can adjust the volume of his corruption, but it takes a lot of concentration and time, and it leaves him more vulnerable than usual, so he doesn't use it often. He must have practiced the octopus thing ages ago..."

Killer snorted, looking at the tiny mollusk form of his dad on the laminated wood floor. "Oh, stars, this is priceless."

The goop began to run again, and the octopus grew distortingly large in a surprisingly short amount of time, expanding and shifting to form regular Goopdad.

Nightmare flopped onto the couch, resuming his original position as a flopped skeleton couch potato.

Error and Fresh both held up a 10.

"You're biased," Horror accused, narrowing his eyes.

Fresh shook his head. "No, that was just super cool! I didn't know Nightmare could do that shape-shifting thing!"

Error shrugged.  
"I mAy bE biAsEd. It iS a dEfiNitE pOsSiBiLitY, eSpEciAlLy wHeN tHe sUbJeCt oF pOsSiBlE biAs iS NiGhTmAre. YoUr pOiNt?"

Cross snickered as Horror rolled his eyes. "Nevermind. Nothing."

Horror held up an 8, Cross and Dust a 9, and Killer a 7.

"By majority vote, Nightmare wins the costume contest!" Dust cheered happily.

Nightmare smiled. "Thank you, thank you. This outcome was unexpected."

"MaY i jUsT sAy, yOu mAkE tHe bEsT oCtOpUs eVeR," Error commented, completely serious. "WhO wAnTs nAcHoS? ThErE'S a tOn aT tHe sNaCk tAblE..."

Nightmare groaned as he watched everyone except him and his datemate teleport off the couch to get the best of the snack table, creating instant chaos. "Aw, Error, they were just under control..."  
Error shrugged. "EhH. ThEy'lL bUrN iT oFf lAtEr."  
"At the expense of the castle," Nightmare huffed, but there was no bite to his tone.

"Oh, sHuSh. If iT gEtS tOo bAd i'Ll KiDnAp a rEpAiR mOnStEr tO FiX iT mYsElF. JuSt eNjOy tHe pArTy." Error scooted slightly closer to Nightmare so he could better view the snack table.

Nightmare noticed Killer and Cross arguing playfully over the last chocolate cupcake. Part of Nightmare wondered how they were even able to eat that many cupcakes in such a short time. He had planned for there being no leftovers for him and Error, however much food he would provide, and had hid some extra food in the pantry and fridge to prepare for the black holes that were his boy's nonexistient stomachs.

The fight was escalating slightly over the cupcake.  
"I'm betting on Cross," Nightmare inputted, watching carefully.  
"ShOuLdN't wE bReAk iT uP?" Error inquired curiously.  
"Nah, if it's about chocolate Cross would throw a fit. If it really escalates over play fighting, i'll interfere. There's no malicious or harmful intent in the air right now," the goopy black skeleton explained.

"...OkAy, tHeN 5 G oN KiLlEr," Error said, relaxing and leaning back on the couch.

Nightmare smiled, watching his boys happily.  
"Deal."

**Author's Note:**

> Drop a comment or kudos if you liked! Feed me~
> 
> SOME HEADCANNON:  
Yes Nightmare can "shapeshift" like that. It's almost like shadow form, but not quite. He kind of liquifies himself and then uses his willpower to form the liquid into a viscous form.  
He can't hold it for long and it's not super solid, but it works for small demonstrations like the contest game.  
He can't do it if he's in high amounts of stress. He has to be calm and focused. Imagine balancing on one foot impulsively, but a bit harder. It takes effort to stay up there, and you can't do it for more than a few minutes at most. After 15-30 seconds, your legs start to burn. That's as close a description as i can get...
> 
> Hope you have a happy Halloween filled with some sort of yummy discount candy! ^w^


End file.
